.con {
    text-align:center;
    width:500px;
    height:500px;
    background-color:#0F9;
    vertical-align:middle;
    display:table-cell;/*非IE6*/
    position:relative;
}
.con2 {
    _position:absolute;
    _top:50%;
    _left:50%
}
p {
    _position:relative;
    _top:-50%;
    _left:-50%;
/*     width:200px; */
/*     border:1px solid #000; */
    display:inline-block
}